attribute vec2 a_position;
uniform vec2 u_resolution;
uniform mat3 u_matrix;
void main() {
    vec2 pos = (u_matrix * vec3(a_position, 1)).xy;
    vec2 clipSpace = (pos / u_resolution) * 2.0 - 1.0;
    gl_Position = vec4(clipSpace * vec2(1,-1), 0, 1);
}